Chinese offshore giant to abandon 171 platforms in 12-year decommissioning drive
Platform removal has already begun with some subsea equipment to be repurposed in major decommissioning programme
China National Offshore Oil Corporation (CNOOC) has plans to decommission 171 oil and gas platforms offshore China over the next 12 years as fields age and reservoirs are depleted, according to the company’s contracting arm.
Field decommissioning at such a scale will pose challenges for CNOOC to quickly replenish its reserves through stepped-up exploration activities, and to develop its discovered resources that have been deemed recoverable.
CNOOC's Offshore Oil Engineering Company (COOEC) said in a recent social media post that platforms in Chinese waters “have entered the peak period of decommissioning” and that by 2035, 171 offshore platforms will have reached the end of their design lives.
CNOOC is eyeing near-term production increases to help close the gap.
By 2025, the company will raise China’s offshore oil production by 8.7% from 2022 levels, to 390 million barrels, and gas by 22.9% to 27.9 billion cubic metres, according to Zhou Shouwei, a former CNOOC president and academician at the Chinese Academy of Engineering.
For 2023, CNOOC’s listed arm CNOOC Ltd has increased its capital expenditure budget by 13%, to between 100 billion and 110 billion yuan (between $14 billion and $15 billion), with about 18% of the spending to go to exploration, 59% to field development and 21% to production.
In 2023, CNOOC Ltd will bring online nine oil and gas projects, including phase one of the giant Bozhong 19-6 gas condensate field in Bohai Bay, the Lufeng 12-3 and Enping 18-6 oilfields in the South China Sea, the Payara oilfield in Guyana and the Buzios 5 and Mero 2 fields in Brazil.
Huizhou unplugged
Late last year, COOEC began mobilising seven offshore vessels for the decommissioning of two major offshore fields, Huizhou 32-5 and Huizhou 26-2, both of which were formerly operated by the CACT Operators group made up of Texaco, Agip, Chevron and CNOOC Ltd.
The decommissioning involves removal of four subsea trees, four subsea pipelines and dozens of cables linking the trees with the platform.
COOEC said that the recovered christmas trees and jumper pipes will be repurposed and used in other unnamed offshore fields after maintenance and refurbishment.
The company has an established track record, having decommissioned a number of offshore fields including Liuhua 4-1 in the South China Sea.
In 2017, the company completed the decommissioning of four fixed platforms operated by Chevron in the Gulf of Thailand.
The workscope covered topsides removal for the four platforms, which were located at the Funan field on Block 12/13 in water depths of about 70 metres, with an option to scrap the steel jackets. The platforms were installed between 1995 and 2000.
The company has signed an agreement with the China-Britain Business Council to work together on offshore platform decommissioning in the UK North Sea.
Ageing oil cluster
Located in the Pearl River Mouth basin of the South China Sea, some 60 kilometres southeast of Hong Kong, Huizhou 32-5 was discovered in 1996 and started production in 1999 from three subsea wells in 113 metres of water.
The field was the first in the South China Sea to be developed as a subsea tie-back to an existing production platform.
The subsea wells are tied back 3.5 kilometres to the Huizhou 26-1 platform through three, six-inch insulated production flowlines.
Discovered in 2016, Huizhou 26-2 is part of Huizhou oil cluster operated by CACT at Block 16/08, 139 kilometres southeast of Hong Kong in water depths of 111 metres.
Texaco, Agip and Chevron formed the ACT Operators Group in 1983 to develop Pearl River Mouth basin hydrocarbon resources. In 1996, CNOOC joined as a fourth partner and the joint operating group changed its name to the CACT Operators Group.
Texaco, Agip and Chevron have equal shares of a 49% interest in the South China Sea oilfields, with CNOOC holding the majority 51%.
CACT’s production sharing contract expired in 2013, leaving the operatorship of the Huizhou 32-5 and Huizhou 26-2 to CNOOC Ltd.
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